BEIRUT - A suicide bomber killed nine people including security officers at a Damascus mosque on Friday, Syria's interior ministry said, in another blow to a fraying UN-brokered truce between President Bashar Assad and rebels fighting for his downfall.

The explosion happened as worshipers were leaving the Zain al-Abideen mosque, which was under heavy security due to its reputation as a launchpad for anti-Assad demonstrations after Friday prayers.

A local resident said security officials at the scene told him a man in military uniform had triggered an explosives vest when he was challenged by soldiers as he walked towards the area.

Many of the body parts scattered across the tarmac were wearing green military-style clothing, the resident said.

There was no immediate claim of responsibility for the blast. But it was close to the site of a Jan. 6 suicide bombing which was claimed by a previously unknown anti-Assad Sunni Islamist group calling itself the al-Nusra Front.

In a statement on state television, the interior ministry said 26 people were wounded in the explosion, one of several bombings on Friday.

"We had been trying to go to pray in the area but they stopped us at a checkpoint. Security weren't letting us in because there are usually protests there," one anti-Assad activist told Reuters by telephone.

"Then we heard the blast. It was so loud and then ambulances came rushing past us," the activist added. "I could see a few body parts and pieces of flesh on the road. The front of a restaurant looked destroyed. People were screaming."

State television showed images of blackened flesh and a mangled hand lying on the road as soldiers and police cleared the area to make way for ambulance crews.

Earlier, a loud blast was heard near a bus station which activists say is often used by pro-Assad militiamen tasked with preventing demonstrations in the capital. Shopkeepers said a Mercedes caught fire but only the driver was wounded.

State media reported three more minor explosions in Damascus in which four people were wounded, and said five policemen were hurt by two blasts in the coastal city of Tartous.